Hitherto, when knitting with a composite yarn composed of a plurality of different filaments with the machine set up for operation in mode (1) above, the only way of ensuring equality of length and tension among all the filaments when they reach the needles has been to twist them together first before feeding them as twisted yarn via the overhead springloaded tensioning arm at the head of the mast. But the only way of achieving such twisting is by bodily spinning all the supplies of the filaments - whether in the form of balls or cones or other kinds of package - as opposed to spinning the filaments after they have been drawn from stationary packages. When the number and variety of packages is large the mechanical problem of handling the whole assembly to be spun calls for precision engineering to combat problems of unbalanced rotating masses, and hence the cost, size and weight are serious limitations on the viability of the system for domestic knitting machines.
In the absence of such elaborate means for equalizing the lengths of and tensions in the component filaments of a composite yarn, the machine operator must constantly finger the separate filaments as they are fed down to the carriage in order to smooth out any individual slackness in the filaments, and the human factor involved can result in its own problems of inequality of tension.
In the case of intarsia knitting, it is common practice for the knitter to gather all the yarns together as they are drawn from their respective cones or balls and to hold them in the fingers of one hand while they are first laid by the other hand on the appropriate needles and crossed over in the usual way in order to preserve the integrity of the finished fabric at each boundary between different yarns, and then knitted by the carriage. By this system accurate control of the tension in each yarn is subject to human error, and irregularities are inevitable, even for experienced knitters. Moreover, this manual system of feed of the yarns to the needle does not eliminate the risk of tangling of the yarns, involving frequent stoppages for corrective action.
It is known to provide a plurality of weights adapted to be threaded onto each intarsia yarn before it is laid in the hooks of the respective needles. Each weight is frictionally suspended on the yarn below the needles so as to maintain a constant tension therein during the knitting action, and care must be exercised before each successive traverse of the carriage to locate each weight sufficiently far below the needles involved with the respective yarn to ensure that the weight, which rises with the yarn as it is drawn up to make the stitches, does not foul the needles while each row of stitches is being made. When using these weights, it is necessary to traverse the carriage slowly, both to enable the knitter to observe all the weights as they approach their respective needles, and also in order to ensure that the speed of formation of each stitch does not produce a jerk in the yarn which, by virtue of the inertia of the weight, would result in random variation in the tension of the yarn.
This system of weighting each yarn in an intarsia pattern allows the weights to swing freely from side to side while they rise towards the needle bed. Once a weight has begun to swing, it induces sympathetic motion in the length of yarn between its respective cone or ball and the weight, which is a prime cause of tangling with the aforesaid manual system of yarn control. The absence of any restraint on the freedom of the weights to move at random thus does nothing to solve the problem of tangling. On the other hand, it adds a new and tedious task for the knitter - that of threading all the weights onto their respective yarns before knitting can start. Each weight consists of a shuttle-like slug having a series of through holes along the length thereof through some or all of which the yarn must be threaded, depending on the thickness of the yarn, before finally being fed through an axial counterbore in the nose. A hook or needle is often required for this operation.